Detection of metals and associated bacteria from Mumbai mangroves and their impact analysis

The distribution of Pb, Ni, Zn, Cu, Cr, Mn, S, P, Na, Ca, K, Si, Al, Fe were studied in the mangrove sediments across five different sites in Maharashtra. Energy dispersive X-ray fluorescence method was utilized for the determination of the elements in the sediment both before and after the monsoon. The spatial variation, as well as the monsoon was seen to affect the metal concentration in the mangroves. A total of 34 and 9 bacterial isolates were isolated pre and post-monsoon respectively. The metal tolerance index of the microbes was increased from a pre-monsoon value of 0.57 to 0.92 post-monsoon against a multi-metal mixture of Pb, Ni, Zn, Cu, and Mn at a concentration of 100ppm. Factor analysis revealed Pb, Zn, and Cu to be the principal factors of pollution both pre and post-monsoon. This could probably be due to the presence of nearby industries which are dumping untreated wastes containing high levels of metals which were confirmed by correlation and PCA analysis. Thus this work brings into light the state of the fast declining mangroves of Maharashtra and the associated microbial population. The data presented here could act as a baseline for other researchers and help civic authorities in checking the disposal from numerous industries of Maharashtra. The metal resistant microbes could be enriched further for in-situ bioremediation of mangrove sediments thereby promoting their growth additionally. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The spatial distribution of several metal elements in mangrove sediments in Maharashtra was studied, with results showing that both spatial variation and monsoon affected metal concentrations. Bacterial isolates were found to increase in metal tolerance post-monsoon, with Pb, Zn, and Cu identified as principal pollution factors pre and post-monsoon. Industrial waste discharge was confirmed to be a major source of metal pollution in the area.